This invention generally relates to imaging systems which communicate with remote devices via networks. In particular, the invention relates to the transfer of digital images from an imaging system to remote devices for archiving, viewing and/or printing. The invention also relates to retrieval by an imaging system of worklist data from a worklist broker via a network.
Conventional ultrasound imagers create two-dimensional images of biological tissue by scanning a focused ultrasound beam in a scan plane and for each transmitted beam, detecting the ultrasound wave energy returned along a respective scan line in the scan plane. A single scan line (or small localized group of scan lines) is acquired by transmitting focused ultrasound energy at a point, and then receiving the reflected energy over time. A B-mode ultrasound image is composed of multiple image scan lines. The brightness of a pixel on the display screen is based on the intensity of the echo returned from the biological tissue being scanned. The outputs of receive beamformer channels are coherently summed to form a respective pixel intensity value for each sample volume in the scanned object. These pixel intensity values are log-compressed, scan-converted and then displayed as a B-mode image of the anatomy which was scanned.
If the ultrasound probe is swept over an area of body, a succession of image frames (corresponding to spaced slices intersecting the body being examined) can be displayed on the monitor. In one type of ultrasound imaging system, a long sequence of the most recent images are stored and continuously updated automatically in a cine memory on a first-in, first-out basis. The cine memory is like a circular image buffer that runs in the background, capturing image data that is displayed in real time to the user. The cine memory acts as a buffer for transfer of images to digital archival devices via the host computer. When the user freezes the system (by operation of an appropriate device on an operator interface), the user has the capability to view image data previously captured in cine memory. The image loop stored in cine memory can be reviewed on the display monitor via trackball control incorporated in the operator interface, and a section of the image loop can be selected for hard disk storage. Any acquired or projected image can be stored internally on the system hard disk or on a magneto-optical disk (MOD) inserted in a disk drive.
In addition to storing images internally, modern imaging systems need to be able to transfer images to various types of remote devices via a communications network. To successfully transfer images, the relevant networking features of the imager must be compatible with the networking features of the destination remote device. In particular, the imager must place the data to be transferred in a format which can be handled by the destination remote device. An attempt to accomplish the foregoing is the adoption of the DICOM (Digital Imaging and Communications in Medicine) standards, which specify the conformance requirements for the relevant networking features. The DICOM standards are intended for use in communicating medical digital images among printers, workstations, acquisition modules (such as an ultrasound imaging system) and file servers. The acquisition module is programmed to transfer data in a format which complies with the DICOM standards, while the receiving device is programmed to receive data which has been formatted in compliance with those same DICOM standards.
The DICOM system is based on the client/server concept. The device which uses a service (on objects) is the client device, while the device which provides the service is the server device. The client device is referred to as a Service Class User (SCU), while the server device is referred to as a Service Class Provider (SCP). The SCU sends a Service Request to the SCP over a local area network (LAN). The SCP sends back a response to the SCU over the same LAN. If the response is affirmative and a communications syntax is agreed upon, an association between the SCU and the SCP is opened and data can be transferred between the two devices. In the DICOM system a device is not limited to one role: it can be both SCU and SCP at different times.
The DICOM system is designed to facilitate the communication of digital images of different types, e.g., X-ray, computerized tomography, magnetic resonance and ultrasound imaging. In an ultrasound imager having conventional DICOM capability, three local real-world activities occur: Image Send, Image Print and Remote Verification. Image Send and Image Print can be done in either automatic or manual mode. Verification of remote DICOM devices configured on the ultrasound imager is performed when the imager is powered up or when requested by the system operator.
All DICOM activities are handled in a queued manner by application software running on a host computer incorporated in the imager. In one type of ultrasound imager, the user can select any image in cine memory to be sent in DICOM format via a LAN to a remote device having DICOM capability. The host computer of the ultrasound imaging system is programmed with DICOM system software which facilitates transmission of image frames from the cine memory to the remote DICOM device via the host computer hard disk and the LAN.
In the conventional ultrasound imager, Image Send can be used in automatic or manual mode, depending on the user configuration. When automatic mode is configured, console keys are used to capture the image and to store it on the hard disk. The request is queued to a DICOM queue manager (preferably implemented in software), which requests an association with the destination remote device. After the association with the remote device has been opened, the queue manager xe2x80x9cpushesxe2x80x9d the image to the remote device without user intervention. The transfer is done in the background while scanning or other operator activities continue. In manual mode, the captured images are archived on the hard disk or on a MOD during the exam(s). Upon completion of the exam(s) the images are tagged using an archive menu and queued to any of the network devices that have been configured on the imager. The images are sent sequentially in the background while scanning or other operator activities proceed. Image Print works much the same way as Image Send, in both automatic and manual modes, the only difference being that the destination device is a printer.
In order to accomplish image transfer, the ultrasound imaging system must know the configuration of the destination remote device prior to attempting to communicate with that device. The configuration data for the destination remote device is typically inputted to the ultrasound imager during software installation by a field engineer (e.g., by inserting an installation disk), although an imaging system can be configured at any time. The constructed configuration file is stored on the hard disk and read into system memory each time the system powers up. When the imager receives an instruction to transmit data to a particular remote device from the system operator, the imager software converts the image data to be transferred into the DICOM format required by the destination remote device, based on the configuration data for that device stored in system memory. The imager also sends a request over the network to the destination remote device to open an association, i.e., to connect the imager to the destination remote device. If the remote device responds in the affirmative, the imager and remote device then agree on which device will act as the server and which as the client. The ultrasound imager also selects the appropriate encoding syntax from those accepted by the remote device. Other communication parameters are also negotiated.
After the DICOM communications protocol has been settled, the association is opened and the imager attempts to send the DICOM-formatted image file (object) to the remote device via the network. The transfer is done in the background while scanning or other operator activities continue. If the remote device is a storage device, each image file is transferred singly in response to a Send request inputted by the operator. If the remote device is a printer configured to print multi-image film, then a number of images are accumulated to make up a multi-image film and an association is opened in response to a Send instruction when a number of images sufficient to fill the multi-image film have been accumulated.
The remote device to which the ultrasound imager sends data can be a printer, a storage device or other device. If the operator interface of the imager has only one configurable Print/Store button, then that button will be configured to initiate data transfer to the destination remote device. The configuration data for the remote device will indicate the type of device to the imager and then the imager will format the data being transferred accordingly. If the operator interface has multiple Print/Store buttons, then each button can be configured to initiate data transfer to a respective remote device. Data transfer to any one of those configured remote devices can then be initiated by pressing the appropriate Print/Store button.
In addition to the digitized image (i.e., pixel data), the DICOM object transferred from the ultrasound imager also includes attribute information extracted from the configuration file. For example, the attribute information may include patient attributes (e.g., patient name and patient identification number), exam attributes (e.g., exam description and exam date), series attributes (e.g., modality type and series date), and image attributes (e.g., image type and numbers of rows and columns). Each attribute has a name, a value representation and a tag. A tag is a number unique to the attribute, e.g., (0040,0100), and is used to identify the attribute. (Different systems use different tags for the same attribute name, which gives rise to incompatibility, as described in more detail hereinafter.) The value representation defines what type of value the attribute can have (e.g., a 64-character string, binary data, etc.).
In accordance with DICOM standards, there are three types of attributes. Type 1 comprises attributes which are mandatory and must always be present with a value; Type 2 comprises attributes which are mandatory but are allowed to be empty; and Type 3 comprises attributes which are optional and are also allowed to be empty. An incompatibility between two devices may arise, for example, if the receiving device requires that a Type 3 attribute be transmitted while the sending device does not include that attribute in its transmission. As a result, even if both devices are configured in accordance with current DICOM standards, the data transfer cannot occur. Thus, even mutual conformance to DICOM standards does not guarantee that two devices can be compatibly connected to each other.
In accordance with a further aspect of the DICOM system as currently implemented, an ultrasound imaging system can retrieve a worklist from a Radiology Information System (RIS) at a hospital via a local area network (LAN). The retrieved worklist may, e.g., comprise all patients to be examined on a particular day using that particular ultrasound imager. The worklist includes the following information for each patient: name, identification number, sex, birth date, accession number, study data, etc. The information retrieval is initiated by the ultrasound imager. A user-interactive Worklist Setup menu is provided which allows the user to select one or more search fields and enter search criteria for each field. The search results are received from the remote worklist broker by the imaging system and stored in memory. This feature gives the system operator the ability to create a local patient list on the imaging system. The user can then select any patient from the worklist for an examination. Selecting a patient from the worklist means that all of the data associated with that patient, which was retrieved from the worklist broker (remote device), will be included with every image of that patient which is stored in image files on the hard disk. Those images are subsequently converted into DICOM objects for transfer to remote printers and storage devices.
Because the DICOM capability is implemented in software, these features of the ultrasound imaging system can be readily upgraded. One goal of such upgrades is to increase the efficiency of the system operator by making the system simpler to operate, e.g., by requiring fewer manipulations to activate a particular operation. Another goal of system upgrades is to increase the ability of the imager to connect rapidly, efficiently and reliably to remote devices on the network, i.e., to increase connectivity.
A known imaging system comprises means for turning off or turning on any DICOM attribute to facilitate communication with a particular remote device. This is accomplished by providing an Attribute Control File which is programmable. However, this feature can be utilized only by the few persons who know which DICOM attributes to turn off. The problem is further complicated because some of these attributes are dependent on other attributes and are order sensitive. Therefore, turning one attribute off without turning off an attribute dependent on the first attribute or changing the order of a sequence of attributes can cause even more problems. This complex arrangement of attributes and their dependencies are described in a 14-volume reference set known as the DICOM 3.0 standard. Service people do not have a copy of this reference set and will not get a copy of this set, because it is very expensive and too complex for the service engineer.
Thus there is a need for a method to simplify the process of configuring an imaging system to a communicate with a new DICOM storage device, printer, or worklist broker. Today, this process is manual in that when the field engineer goes to a site to configure an imaging system to communicate with a newly installed DICOM device, the field engineer will go to a Device Configuration screen and manually fill out the configuration information for the remote device being added. The configuration information, including what attributes are mandatory, varies from device to device and even from revision to revision of the same type of devices. There is a need for a simple method whereby a field engineer or other system user can configure the attributes which an imaging system will send to a particular remote device without knowing or inquiring which attributes that particular remote device requires.
The present invention is incorporated in an imager which is programmed with at least one task for constructing objects to be transferred to a remote device. The imager may comprise multiple tasks for communicating with a respective multiplicity of remote devices. Each task is configurable by the user to construct objects compatible with a particular remote device, e.g., a storage device or printer. Each configured remote device can then be xe2x80x9cactivatedxe2x80x9d, with the understanding that the term xe2x80x9cactivationxe2x80x9d, as used in this context, means that the imager has a task configured for that remote device, not that the remote device itself is in any sense remotely activated by the imager. In accordance with the preferred embodiment, the tasks are configured to comply with DICOM standards.
In accordance with the DICOM standard, a DICOM task can be designed to convert an image file, comprising image frame data and attribute data, into a DICOM-formatted object, also comprising image frame and attribute data. That DICOM object must conform not only to the DICOM standards and the imaging and formatting requirements of the particular device, but also to the attribute requirements (i.e., tags) of the particular remote device destined to receive that DICOM object. After construction, the DICOM object can be sent to the destination storage device or printer. In addition, another DICOM task in the imaging system can be designed to send a modality worklist query to a remotely located device, e.g., a worklist broker. That query must also conform to DICOM standards and be compatible with the formatting and attribute requirements of the receiving device.
The imaging system incorporating the present invention has a separate Attribute Control File for each different activated configured remote device. Each Attribute Control File, in ASCII format, is a mapping of which attributes should be included and which attribute tags should be used in every image or worklist query transmitted to the remote device associated with that Attribute Control File. Each DICOM task will convert each image file or worklist query file into a DICOM object comprising the attribute data dictated by the Attribute Control File associated with the corresponding DICOM task. A host computer of the imaging system is programmed with an Attribute Control Engine which controls the inclusion of particular attributes and attribute tags in the DICOM objects constructed by each DICOM task. In particular, in response to queries from a DICOM task, the Attribute Control Engine will instruct that DICOM task concerning which attributes and what attribute tags should be included in the DICOM object being constructed. The Attribute Control Engine in turn obtains that information from the Attribute Control File associated with that DICOM task.
In accordance with the preferred embodiment of the present invention, a field engineer is able to select a prestored configuration file for a particular device from a configuration file library stored on the imaging system hard disk. The field engineer selects a configuration file by interacting with a graphical user interface, i.e., by selecting from a drop-down pick list of equipment identified by make and model. The pick list itself is constructed from information extracted from the configuration file library. The data in the selected configuration file from the library is supplemented, and optionally modified, to create a new configuration file which is copied into or installed at a different address on the hard disk when installation is finished. During subsequent powering up of the imaging system, the new configuration file will be copied into system memory, and an attribute section of the new configuration file will be copied to an Attribute Control File in system memory, for use during system operation.
In accordance with the preferred embodiment of the invention, each prestored configuration file includes presets which constitute the best imaging and formatting settings as determined by specialists at a central service facility. This reduces the amount of time which a field service engineer must spend to adjust the settings by trial and error when a new imaging system is installed or when an existing imaging system is being configured to communicate with a new remote device. The presets may include certain image quality settings, image format settings, and so forth. Once the best settings have been determined for a particular device, the service center personnel will create a configuration file for that device. This configuration file will also include the attribute information for the particular remote device. The prestored file will serve as a default configuration for that remote device. As many files as possible will be created to form a library of configuration files. This library of files can be modified at a subsequent time if need be.
In accordance with the preferred embodiment, the configuration file library will be placed on the install disks to be installed with every new installation. Alternatively, the configuration file library can be added later. The library will preferably include configuration files for all commercially available devices which could conceivably be connected to a DICOM communications network. Preferably the field engineer can adjust the prestored settings if necessary.
Although the preferred embodiment of the invention is disclosed below in the context of imaging systems which communicate with remote devices using the DICOM standard, it will be appreciated that the broad concept of the invention has application with any digital image communications standard or protocol that requires configuration of the imaging device as a function of different requirements of different receiving devices.